Mold



Nov. l, 19%., H E, MCWANE 2,134,829

MOLD

Original Filed Nov` 30, 1955 2 Sheetsmsheet l Nov. 1, 1938. UH. E.MGWAN@ A21.134,329

MOLD

Original Filed NOV. 50, 1935 2 Sheets-Smet 2 Patented Nov. 1, 1938UNITED VSTATES TENT FFICE Application November 30, 1935, Serial No.52,432 Renewed March 25, 1938 I0 Claims.

My invention relates to molds and more particularly to molds of thepermanent type adapted to be made of hard material and intended forcontinuous re-use.

Such molds are customarily made of metal or some metallic alloy, and ifproperly used should last a considerable length of time. I have found,however, that in casting certain types of articles, lthese permanentmolds produce cracks and fractures in the casting. This is believed tobe due to temperature changes in the metal of the casting which producepoints of strain. For instance, in casting plow points there are certainprotuberances and depressions or recesses on the plow point which in apermanent mold cause strains to be produced upon the solidifying of themetal of the casting.

I have heretofore shown a type of core which I have adapted forpermanent molds which is movable under stresses and strains set up byreason of temperature changes of the metal which forms the casting.

In the present application I not only show a movable core to produce arecess in the casting, but also a movable mold section which is adaptedto cast protuberances on the castings. The method of forming the recessand protuberances is such that the strains which would otherwise producecracks and fractures in the casting are eliminated or compensated for bymovement of the parts.

It is an object of my invention to produce a mold which will permit ofquick cooling of the molten material without producing objectionablestresses and strains in the molten material whereby fractures and cracksin the molded article may be eliminated.

A further object of my invention is to provide a structure foraccomplishing the objects herein which is strong and durable and whichwill last for continued periods of constant use.

A still further object of my invention is to produce a structure whichis simple and cheap and easy of repair and replacements.

With these and other objects in view, which may be incident to myimprovements, the invention consists in the parts and combinations to behereinafter set forth and claimed, with the undertsanding that theseveral necessary elements comprising my invention may be varied inconstruction, proportions and arrangement, without departing from thespirit and scope of the appended claims.

-In order to make my invention more clearly understood, I have shown inthe accompanying (Cl. .Z2-136) Figure 2 is a plan view of another halfof a mold looking into the interior;

Figures 1 and 2 are halves of a mold which is adapted to the casting ofplow points.

Figure 3 is a view taken along the line 3-3 of Figures 1 and 2, when thetwo halves of the mold are in place and in engagement with each other;

Figure 4 is a view taken along the line 4-4 of Figure 3, looking in thedirection of the arrows;

Figure 5 is a View taken along the line 5--5 of Figure 3, looking in thedirection of the arrows;

Figure 6 is a sectional view illustrating what I believe to be theaction of the mold in casting during the cooling of the casting Withinthe mold;

Figure 7 is a perspective view of a plow point.

Referring to the drawings I have shown two parts of a permanent moldconstruction I and 2. The bottoms of these mold parts are indicated bythe numerals 3 and 4. The mold parts are adapted to be filled through agate 5 in the mold part 2 which is shown in dotted lines. The mold partsare filled from the bottom up. I have shown fastening means 6 on themold part 2 and fastening means 'I on the mold part I for fastening themold parts together. The means for holding them together in operativeposition to be lled constitutes no part of this invention and is notshown.

In actual operation the mold parts are adapted to be opened and thecasting removed, the mold parts closed, the refilling operationaccomplished, all occurring in rapid succession.

Mold part I is provided with a fluid chamber 8 and the mold part 2 witha fluid chamber 9.

.Chamber 8 is provided with apertures I0 and chamber 9 with apertures II through which cooling fluid may be passed to the chambers 8 and 9,respectively, to cool the mold to produce proper chilling and permit therapid operation of the mold.

Each chamber 8 and 9 is lined with a ductile metal liner I2 which may bewelded onto the interior of the chamber or otherwise suitably fastened.This is done in order `to minimize the danger of cracks forming in themold which will permit water from the chambers 8 or 9 to enter the moldand come in contact with heated portions, thus possibly producingexplosions. .The metal liner I2 is the subject matter or anotherapplication which I have lust nied.

Chamber l is provided with a cover I8 and chamber l with a cover I4which are welded as indicated at Il and I6, respectively, to thechambers. Chamber l is provided with a tubular member I1 which passesthrough the chamber and is held in place by welding, as indicated at Il,at its inner end, and at its outer end by welding as indicated at I9.

Likewise, there is a tubular member 2l which passes through the chamber8 which is held at its inner end as indicated at 2| by'welding, and atits outer end by welding, as indicated at 22, to the cover Il.

Within the tube I1 ls a compression spring 23 which bears at its lowerend against a movable mold section 24 having tapered body portion 2lprovided with an upstanding centering lug 2l over which one end of thespring 23 nts. The other end of the spring 2l nts over a lug 21 formedon a cover 2l that is screwed as at 2l into the tubular member I1.

The cover 28 is provided with a wrench or screw aperture 30 whichpermits the cover to be screwed in place, thus compressing the spring 22and forcing the tapering mold section 24 inwardly against its taperingseat in aperture II formed in the mold part 2. Mold section 24 isprovided with an aperture 22 which is adapted to receive a portion 22 ofthe finished casting (see Fig. 7). There is formed in the interior ofthe mold an annular depression 33 which forms a shallow boss n' on thecasting. The plow point is formed with an upwardly projecting surface34', see Figure '1, which is formed by the corresponding depression 34in the mold part 2.

'Ihe face oi' the casting (not shown in Figure '1) is formed in the moldpart I. There is provided a frusto-conical aperture 35' which passesthrough the body of the point and is formed by a core member I6 whichhas a frusto-conical section 21, another frusto-conical section 38, anda third smaller frusto-conical section 39.

Ihe core 26 is provided with a lug 40 over which fits one end of acompression spring 4I. The

other end of the compression spring fits over a lug 42 formed in coverplate 43 which is screwthreaded as indicated at 44 into the tubularmember 2II. The cover plate 43 is provided with a screw or wrench slot45 whereby it may be screwed into place and force core 26 into the mold.

The lug 32' is provided with a specially formed surface 41' which isformed by a tit 41 which projects from the face of the mold part 2 intothe aperture 32 formed in the mold section 24 (see Figure 4).

In operation, when the metal of the plow point shrinks due to cooling,the movable nature oi' the frusto-conical mold section 24 and thefrustoconical core 30 allow contraction to take place without crackingthe metal of the plow point or subjecting it to harmful strain. 'I'heexact nature of the movement of the core 36 and of the mold section 24is not thoroughly understood. It is believed that there is a givingbetween the parts which may occur in the manner illustrated in Figure 6,but I do not wish to be limited to any particular theory oi' operation.Suilice it to say that I have actually'made and tested many times moldsembodying sections such as 24 and cores such as It. and iind that theconstruction illustrated is eiiicacious and does prevent injury to thecastings. Therefore, I- want it distinctly understood that if themovement of the parts is not exactly as illustrated in Figure 6, I shallnot be bound by this theory of operation., I have illustrated andexplained the construction of a practical device which does the work andconstitutes in my opinion a useful advance in the art.

While I have shown and described the preferred embodiment of myinvention, I wish it to be understood that I do not corinne myself tothe precise details of construction herein set forth, by way ofillustration, as it is apparent that many changes and variations may bemade therein, by those skilled in the art, without departing from thespirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. A permanent mold construction for relieving strains in castingscomprising a tapered movable mold section adapted to form a protrusionon the casting, said section being adapted to give in the direction ofstrain set up by reason of temperature changes in the casting.

2. A permanent mold construction for relieving strains in castingscomprising a mold section having a depressed area adapted to form aprotrusion on the casting, an aperture in the mold in which the sectionlies, and means to yieldingly hold the section in place while permittingit to give in the direction of strain occurring through temperaturechanges.

3. A permanent mold construction for relieving strains in castingscomprising a tapered mold section having a depressed area adapted toform a protrusion on the casting, an aperture in the mold in which thesection lies, and means to yieldingly hold the section in place whilepermitting it to give in the direction of strain occurring throughtemperature changes.

4. A permanent mold construction for relieving strains in castingscomprising a tapered mold section adapted to form a protrusion on thecasting, a tapered aperture in the mold in which the section lies, andmeans to yieldingly hold the section in place while permitting it togive in the drection of strain occurring through temperature changes.

5. A permanent mold construction for relieving strains in castingscomprising a mold section having a depressed area adapted to form aprotrusion 'd on the casting, an aperture in the mold in which thesection lies, and spring means pressing the section in the direction ofthe casting.

6. A permanent mold construction for relieving strains in castingscomprising a tapered mold section having a depressed area adapted toform a. protrusion on the casting, an aperture in the mold in which thesection lies, and a spring pressing the section in the direction of thecasting.

'7. A permanent mold construction for relieving strains in castingscomprising a tapered mold section adapted to form a protrusion on thecasting, a tapered aperture in the mold in which the section lies, and aspring pressing the section in the direction of the casting.

8. A permanent mold construction for relieving strains in castingscomprising a mold section having a depressed area adapted to form aprotrusion on the casting, an aperture in the mold in which the sectionlies, a spring pressing the section in the direction of the casting andmeans permitting the removal of the spring and section.

9. A permanent mold construction for relieving strains lncastingscomprising a tapered mold section having a depressed area.adapted to form a protmsion on the casting, an aperture in the mold inwhich the section lies, a spring pressing the section in the directionof the casting, and means permitting the removal of the spring andsection.

10. A permanent mold construction for relieving strains in castingscomprising a, tapered mold section adapted to form a. protrusion on thecasting, a. tapered aperture in the mold in which the section lies, aspring pressing the section in the direction of the casting, and meanspermitting I removal of the spring and section.

HENRY E. McWANE.

